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A073774 Number of plane binary trees of size n+3 and height n. 4
0, 0, 0, 4, 68, 376, 1440, 4736, 14272, 40576, 110592, 291840, 750592, 1890304, 4677632, 11403264, 27443200, 65306624, 153878528, 359399424, 832831488, 1916272640, 4380950528, 9957277696, 22510829568, 50642026496, 113413980160 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

LINKS

H. Bottomley & A. Karttunen Derivations of the formulae for the diagonals of A073345 & A073346.

FORMULA

a(n < 3) = 0, a(3) = 4, a(n) = 1/12 * 2^(n-1) * (2*n^3 + 9*n^2 - 23*n - 78) or a(n) = 2^(n-2) * |A073775(n-3)| from n >= 3 onward.

MAPLE

A073774 := n -> `if`((n < 3), 0, (2^(n-2))*abs(A073775(n-3)));

CROSSREFS

A073774(n) = A073345(n+3, n). Cf. A014480, A073773, A073775.

Sequence in context: A003360 A083931 A133881 * A141032 A156084 A000658

Adjacent sequences:  A073771 A073772 A073773 * A073775 A073776 A073777

KEYWORD

nonn

AUTHOR

Antti Karttunen Aug 11 2002

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Last modified February 16 13:30 EST 2012. Contains 205909 sequences.